WO02/078646 discloses a dental composition containing benzoyl peroxide and for use as a root canal sealant.
Protective dental treatment for avoiding mechanical, bacterial or chemical trauma, in particular primary and secondary caries, is of increasing importance in the dental field. Pit and fissure sealants are known as compositions used in protective treatments of occlusal surfaces. Sealant materials for protective treatment of cervical surfaces exposed by gingival retraction caused by long-standing periodontitis are also known. However, such materials are characterized by high abrasion and require frequent replacements.
Dental materials can be divided into chemically (thermally) curable materials and materials polymerizing by exposure to light. Thermal polymerization is usually severely limited for applications on living tissue or other heat sensitive surfaces. Highly reactive initiators and the presence of amine accelerators are usually required whereby the shelf-life of a one-component composition is deteriorated or multi-component systems are required.
Pit and fissure sealants are typically based on methacrylate monomers. Self-curing compositions are typically two-component systems including in a first component one or more methacryl ate monomers and at least one component of a free radical liberating (redox) polymerization system for said monomer(s). The monomer composition may include the peroxy type catalyst (oxidant) which is later contacted with a second component including the reducing agent (reductant) shortly prior to dental use. In case of a sealant composition, the viscosity of the composition must be low enough to allow thorough penetration of fissures and intricate interdental spaces with no air bubbles prior to polymerisation. The handling of a two-component system for providing a low-viscosity composition is highly problematic.
Light-curing compositions contain methacrylate monomers and an initiator system in a single pack. However, the storage stability of such compositions depends on the absence of light and the careful handling of the composition prior to polymerisation.
A primary object of the invention is to provide polymerizable dental sealant compositions wherein the foregoing and related disadvantages are eliminated or at least mitigated to a substantial extent.
Another object of the invention is to provide polymerizable dental sealant compositions capable of undergoing a rapid rate of cure to produce a polymerizate having strong adhesion to dentin or enamel and having excellent protective properties as a pit or fissure sealant or a sealant for exposed cervical surfaces.
Yet another object of the invention is to provide such a sealant composition having good structural stability within the environment of the human oral cavity. Still another object of the invention is to provide such a composition wherein any requirements for using higher catalyst concentrations to achieve effective rate and degree of cure are obviated.
Yet a still further object of the invention is to provide a process of utilizing such compositions to prepare a high quality polymerizate.